Referring to FIG. 8, a conventional selective one-way bit-driving apparatus 70 is provided between a handle 72 and a bit 74. The selective one-way bit-driving apparatus 70 includes a shaft 76 and a bit receiver 78. The shaft 76 includes a first section for connection with the handle 72 and a second section. The bit receiver 78 includes a first space for receiving the second section of the shaft 76 and a second space for receiving the bit 74. Teeth 79 are formed on the wall of the first space of the bit receiver 78. The shaft 76 drives the bit receiver 78 in selective one of two directions through two one-way drivers 80. A detent 82 is installed on the second section of the shaft 76. A switch 84 in the form of a ring is provided around the second section of the shaft 76. The switch 84 includes two recesses 86 in an internal face in order to receive the selective one-way drivers 80. Moreover, the switch 84 includes, in the internal face, three recesses 88, one of which receives the detent 82 in order to keep the switch 84 in selective one of three positions on the second section of the shaft 76. Each of the one-way drivers 80 is engaged with the teeth 79 at only one point. The form of the one-way drivers 80 is not compliant with that of the teeth 79. These factors allow the one-way drivers 80 and the teeth 79 to slide relative to and wear away each other. Hence, this engagement cannot transmit adequate torque from the shaft 76 to the bit receiver 78.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.